"To get this effect, spice up your broccoli with broccoli sprouts, mustard, horseradish, or wasabi. The spicier, the better; that means it's being effective," said Elizabeth Jeffery, a University of Illinois professor of nutrition who was involved in the study.

Myrosinase helps to form sulforaphane, which is how broccoli gets it cancer-fighting abilities, said co-author Margarita Teran-Garcia.

The researchers paired broccoli with broccoli powder and measured the presence of certain compounds in the blood streams of eaters 30 minutes later. Three hours later, the blood was tested again and the compounds were found to be at their peak.

While broccoli powder itself does not have any myrosinase in it, broccoli does, and the two mixed together to form the necessary amount of sulforaphane.

The spicy additions to broccoli even helped when people overcooked broccoli — which should be lightly steamed for two to four minutes for maximum nutrition — a common occurrence.

Radishes, cabbage, arugula, watercress and Brussels sprouts will also increase the effectiveness of broccoli.

Three to five servings of broccoli a week can boost cancer-protective benefits, say scientists.

"But it pays to spice it up for added benefits and find ways to make it appealing so you don't mind eating it if you're not a broccoli fan. I add fresh broccoli sprouts to sandwiches and add them as one of my pizza toppings after the pie is out of the oven," said Jenna Cramer, lead author of the study.